This article is the subject of a legal complaint made on behalf of T&L Sugars Limited.

The British sugar giant Tate & Lyle has imported large volumes of sugar from Cambodia through a supplier that is accused of using child labour and being complicit in expropriating land and inflicting violence on local people.

Tate & Lyle – which is the EU's largest cane sugar producer and whose ingredients are used in a wide range of foods around the world – , has used the Thai KSL Group since 2011 for its supplies from Cambodia. However, KSL is alleged to have been complicit, along with the Cambodian government, in the eviction of people from their land, arson and theft.

A worker loads sugarcanes onto an ox-cart at a farm in Kandal province. Sugar is big business in Cambodia but many farmers say they have to yet reap any profits. Photograph: Pring Samrang/Reuters

Villagers interviewed by the Guardian claim they had their homes and property destroyed and land taken. They also say they were subjected to physical violence and that one of them was killed during the process of land clearance for plantations.

Children as young as nine work on Cambodian plantations run by KSL.

Tate & Lyle is being sued by Cambodian families who claim the company knew – or should have known – of the allegations against its supplier. Tate & Lyle is the EU’s largest cane sugar producer. Photograph: Chris Ratcliffe/Bloomberg

The allegations against Tate & Lyle call into question the ethics of the sugar industry's supply chain in much the same way that the clothing and precious metals sectors have been scrutinised.

Two hundred Cambodian families have launched a lawsuit against Tate & Lyle in the high court in London. The families claim the company knew – or should have known – of the allegations against its supplier and say they want to be compensated for the value of sugar grown on land they allege still belongs to them.

Many of those who claim to have lost land say they have since been forced to work on the plantations, where they can earn as little as 79p a day cutting down 1,000 stems of sugar cane.

Activists say nearly 100,000 hectares (247,000 acres) have been cleared in three provinces to make way for sugar plantations since 2006. Most of that land, they argue, has been stolen from subsistence farmers. "I had to pull my kids out of school and send them to work on the plantation after they took our land away because we couldn't afford to eat," said Chea Sok, 38, one of the claimants in the lawsuit. "We lost five hectares, around $2,500 of income, and got no compensation, not even one riel."

Tate & Lyle contends that it used third-party auditors to vet KSL for legal, ethical and sustainability standards and believes that land concessions were purchased legitimately, compensation paid to villagers and that the sugar it buys is free of human rights abuses. However, it has also clarified that it is ready to break its contract with KSL if it finds the supplier has been guilty of any wrongdoing.